<?php
/**
* 通用的树型类，可以生成任何树型结构
*/
class pf_tree {
	/**
	* 生成树型结构所需要的2维数组
	* @var array
	*/
	public $arr = array();

	public $ret;
	public $icon = array('│','├','└');
	public $nbsp = "&nbsp;";

	/**
	* 构造函数，初始化类
	* @param array 2维数组，例如：
	* array(
	*      1 => array('id'=>'1','parentid'=>0,'name'=>'一级栏目一'),
	*      2 => array('id'=>'2','parentid'=>0,'name'=>'一级栏目二'),
	*      3 => array('id'=>'3','parentid'=>1,'name'=>'二级栏目一'),
	*      4 => array('id'=>'4','parentid'=>1,'name'=>'二级栏目二'),
	*      5 => array('id'=>'5','parentid'=>2,'name'=>'二级栏目三'),
	*      6 => array('id'=>'6','parentid'=>3,'name'=>'三级栏目一'),
	*      7 => array('id'=>'7','parentid'=>3,'name'=>'三级栏目二')
	*      )
	*/
	public function init($arr=array())
	{
		$this->arr = $arr;
		$this->ret = '';
		return is_array($arr);
	}

	/**
	 * 获取线型数组
	 *
	 * @return 
	 */
	public function get_line($myid='0', $level=0)
	{
		$level++;
		$savetree = $child = array();
		foreach ($this->arr as $key=>$var)
		{
			if ($var['parentid'] == $myid)
			{
				$var['level'] = $level;
				$id = $var['id'];
				$child[] = $var;

				$res = $this->get_line($id, $level);
				if (!empty($res))
				{
					$child = array_merge($child, $res);
				}
			}
		}
		return $child;
	}

	/**
	 * 得到树型结构
	 * @param int ID，表示获得这个ID下的所有子级
	 * @param string 生成树型结构的基本代码，例如："<option value=\$id \$selected>\$spacer\$name</option>"
	 * @param int 被选中的ID，比如在做树型下拉框的时候需要用到
	 * @return string
	 */
	public function get_tree($myid)
	{

		$child = $this->get_child($myid);
		if(is_array($child))
		{
			foreach($child as $key=>$a)
			{
				$id = $a['id'];
				$res = $this->get_tree($id);
				if (false !== $res && is_array($res))
				{
					$child[$key]['sub'] = $res;
				}
			}
		}
		return $child;
	}

	public function get_tree2($myid, $str, $sid = 0, $adds = '', $str_group = ''){
		$number=1;
		$child = $this->get_child($myid);
		if(is_array($child)){
			$total = count($child);
			foreach($child as $id=>$value){
				$j=$k='';
				if($number==$total){
					$j .= $this->icon[2];
				}else{
					$j .= $this->icon[1];
					$k = $adds ? $this->icon[0] : '';
				}
				$spacer = $adds ? $adds.$j : '';
				$selected = $id==$sid ? 'selected' : '';
				@extract($value);
				$parentid == 0 && $str_group ? eval("\$nstr = \"$str_group\";") : eval("\$nstr = \"$str\";");
				$this->ret .= $nstr;
				$nbsp = $this->nbsp;
				$this->get_tree2($id, $str, $sid, $adds.$k.$nbsp,$str_group);
				$number++;
			}
		}
		return $this->ret;
	}
	/**
	* 得到子级数组
	* @param int
	* @return array
	*/
	public function get_child($myid)
	{
		$a = $newarr = array();
		if(is_array($this->arr))
		{
			foreach($this->arr as $id => $a)
			{
				if($a['parentid'] == $myid)
				{
					$newarr[$id] = $a;
				}
			}
		}
		return $newarr ? $newarr : false;
	}


}

/*$t = new pf_tree;
$arr = array(
1 => array('id'=>'1','parentid'=>0,'name'=>'一级栏目一'),
2 => array('id'=>'2','parentid'=>0,'name'=>'一级栏目二'),
3 => array('id'=>'3','parentid'=>1,'name'=>'二级栏目一'),
4 => array('id'=>'4','parentid'=>1,'name'=>'二级栏目二'),
5 => array('id'=>'5','parentid'=>2,'name'=>'二级栏目三'),
6 => array('id'=>'6','parentid'=>3,'name'=>'三级栏目一'),
7 => array('id'=>'7','parentid'=>3,'name'=>'三级栏目二')
);

$t->init($arr);
$res = $t->get_tree(0);
var_export($res);
//$parent = $t->get_parent(7);
//$parent = $t->get_line();
//var_export($parent);
*/
?>